This invention relates to valve control arrangements for multi-valve internal combustion engines equipped with lift valves for intake and exhaust and provided with pivoted levers for valve actuation.
U.S. Pat. No. 5,031,586 discloses an in-line internal combustion engine having three inlet valves and two exhaust valves for each combustion chamber in which pivoted levers are provided between the lift valves and cams on two camshafts. The pivoted levers have one of their ends engaging the lift valves and the other ends engaging hydraulically positioned supporting elements. The supporting elements are mounted in receptacles in the cylinder head which are supplied with oil from a lubricating system for the internal combustion engine. In this case, the valve control arrangement includes camshafts having longitudinal axes extending transversely to and between the longitudinal axes of the supporting elements for the pivoted levers and of the corresponding lift valves. For each cylinder, the exhaust valves and the inlet valves are combined into two groups. All of the supporting elements for the exhaust valves are arranged so that their longitudinal axes, as viewed in the longitudinal direction of the exhaust valve camshaft, lie on the outside of the plane of the exhaust valves relative to the longitudinal center plane of the cylinder head. Similarly, on the other side of the longitudinal center plane of the cylinder head, the plane of the supporting elements for the two intake valves is on the outside of the plane of the valves relative to the center plane of the cylinder head. The third intake valve for each cylinder is centrally located and the hydraulic supporting elements for those valves are located adjacent to the longitudinal center plane of the cylinder head so that their longitudinal axes are inside the planes of longitudinal axes of the other valves. The three supporting elements of the intake valves for each cylinder are therefore arranged in a zigzag pattern in the longitudinal direction of the cylinder head.
Furthermore, German Offenlegungsschrifft No. 42 35 103 discloses a valve control arrangement in which hydraulic supporting elements are integrated coaxially in the pivoted levers for the lift valves and the levers are mounted on pivots. In this valve control, the geometric pattern is arranged so that, as viewed in the longitudinal direction of each camshaft, the longitudinal axis of the camshaft is located between the longitudinal axis of a lift valve and a longitudinal axis parallel thereto extending through the lever pivot, whereas the longitudinal axis of the camshaft for the cylinder lying adjacent thereto is located outside the region between these two parallel longitudinal axes.